Two of Zac's most SCORCHING missions in one book: SUDDEN DROP and TOMB OF DOOM ! First, in Sudden Drop, Zac uncovers an evil plan to melt the polar ice caps and flood the entire world! Zac has to go into the desert to stop BIG from hijacking a secret water supply. Then, in Tomb of Doom, Zac has to rescue one of GIB's best agents who has gone missing near the Vanishing Tomb, somewhere in the desert region of the Amber Sands. The Vanishing Tomb keeps vanishing and has ancient booby traps. Zac will need more than a bag full of super-cool spy gadgets to complete this mission and get out alive.